Nick Walker (for WG3) Snowmass, 2001

Transcription

1 Nick Walker (for WG) Snowmass, 2

2 General Layout Complete Lattice Final Telescope Beam switchyard Collimation System - basic concept - spoiler protection (MES) - halo tracking (dynamic aperture) Hardware Etraction line & Dump

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5 Microns e+ wiggler arc MES E-COLL β-coll & DIAG CCS FT 4 2 Beam envelope σ σ y Beam ais /m

6 5 mm e+ wiggler arc MES E-COLL β-coll & DIAG CCS FT 5 5 Dispersion beam ais (m)

7 Weak doublet Final telescope stretched to put beamstrahlung dump in the main dump hall

8 laser laser interferometer interferometer instrumented instrumented mask mask 2K cryostat 2K cryostat 8. mrad 8. mrad 54.5 MRAD 54.5 MRAD quadrupole quadrupole VTX VTX 27.5 MRAD 27.5 MRAD Ø48mm 25T/m IP IP 24mm cylindrical mask with 24mm pair cylindrical L monitor mask with pair L monitor stripline BPM cavity BPM stripline BPM cavity BPM L*=m

9 Double bend achromat system to reduce synch. rad. effects. ( light sources)

10 σ /y = / 7 µm ESPOI D = mm Σ /y /σ /y = / 8 φ = 45 φ y = 5 σ = µ m σ y = 7µ m a /y =.5 /.5 mm 4 beta function (m) β β y Includes factor cos(45º/2) Beam Ais (m)

11 plane /mm y plane /mm plane /mm σ beam 8σ y mask doublet VTX ±8σ y ±8σ y ±8σ y ±σ ±σ ±σ IR ais (m)

12 GEANT studies suggest X Ti spoiler will survive one design bunch

13 2 mm Horizontal Offset (mm) D = 2 mm D = β = 4 mm β = 4 m kicker MP BPM ~8 m (67 ns) septum ~ m ~ m 2 µ r 5.7 mr ~4 m (4 ns) energy spoiler ~24 cm Beam Ais (m) 2 to 5% E/E kicker failure.5% kicker flat top ±2% ±.5% PS ripple

14 π + = ϕ π + = ϕ ) ( ) ( 2 2 y y n n ' δ = = K D R R 6 ' δ = D K -I π/2 π/2 π + = ϕ ) ( ) ( 2 2 y y n n ' δ = = K D R R 6 ' δ = D K K 2 K K 2 collimator linear dispersion non-linear dispersion (rd-order) skew-setupole skew-setupole octupole

15 (a) design (linear) beam (b) spoiled beam 5 5 Y / µ m Y / µ m -5-5 σ - σ y y ( δ ( δ ) = ) 6 X / µ m K 2 K R 2 β β y ε ε y D δ X / µ m factor 6 in σ y at P/P = 2% P/P = 2%

16 nd -.5%<δ<+.5% MES magnets only With 2 nd -order δ compensation

17 (a) Horizontal (b) Vertical rel. increase in σ FFS only 2.5 BDS 2 e- e-.5 e+ e+ FFS only BDS MES non-linear Magnets OFF P/P (%) P/P (%) MES non-linear Magnets ON

18 (Dynamic Aperture) 5 5 particles tracked tracked Loss Loss (%) (%) energy energy betatron betatron ±6.25σ ±σ ±σ y y %< P/P<+.5% CCS CCS spoilers spoilers Z (m) (m)

19 (Dynamic Aperture) - - / σ / σ 2 2 collimation depth collimation depth y/σ y / σy y collimation depth collimation depth -5-5 / σ / σ P/P (%) P/P (%) 2 2 No particles outside collimation depth (particle scattering not included) inititial inititial cut at +.5% cut at +.5% - - ~5/5 (5%) X-Y space at entrance of final doublet 5 5 y/σ y / σy y -2-2

20 Loss (%) Loss (%) 5 5 ~5% of 5 particles 4 4 energy energy tracked hit CCS collimators 2 2 betatron betatron CCS spoilers CCS spoilers Z (m) Z (m) Wayward beam can hit these spoilers CCS spoiler hits mapped back to eit of linac

21 (a) narrow switchyard quadrupole (b) Ø2mm quadrupole (c) C dipole (d) H dipole Dipoles (H/C).8m Ø2mm.2-.24T 85 Quads.5-2.m Ø2/4/2mm.72-.4T 9 Setupoles.5-2.2m Ø2mm.26-.5T 2 Octupole.5m Ø2mm.29T 288

22 Drift tolerances (2% σ* y increase) Based on e- p/p Count Sensitivity ( µm ) PS (field) stability: typical -4 (few at -5 )

23 Need to reduce and localise beam loss to <ppm 25GeV etraction line looks OK 4GeV etraction line needs more study (bigger P/P) Beam etracted vertically (-5mrad) 54m ES separators (a la LEP) (5kV/m for 25GeV) 6m vertical septum (~.T)

24 Beam power.2 MW (6.8 Undisrupted beam size on window =.4 mm 2 Fast sweeper magnets sweep bunch train with r = 5cm Limits T 4º C MPS issue Pump Pump 2 Emergency / Commissioning C 4 C Heat 75 C Echanger 5 C A 8 C Gas Analysis Heat Echanger B Secondary Loop Gas Buffer (He) Pressure Control 7 C Primary Loop 2MW / T=K / 95kg/s Hydrogen Recombiner W ater Dump normal water, m, bar, 2 entrance windows General Cooling Water Water Level Control % to % of total flow Spent Beam Water Filter Delay Line

25 Complete system works but there is room for improvement FF system OK, but bandwidth could be improved Collimation systems and in particular MP system needs review/more work What can Raimondi do for TESLA? Still lots to do